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#11
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Do you crab or forward slip in X wind landings
Side slip is the easiest and most powerful form of crosswind correction. Simply use the rudder to keep the nose of the glider parallel to runway center line and lower the upwind wing enough to counter the wind. To much bank and you drift upwind of centerline. Side slip can be maintained all the way to the end of the roll out just by keeping the upwind wing low. If the cross wind is to strong for this method you shouldn't be flying or you should select a different runway.
Crab Requires a transition to a side slip just above the ground and almost guarantees a side loaded landing either from kicking to late or to soon and not getting into the side slip quick enough. Forward slips are not really for crosswind correction they are more for glide path control. |
#12
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Do you crab or forward slip in X wind landings
Side slip for all the above reasons, especially for instruction. Translating from crab to slip in the flair or just at touchdown is unnecessarily complex. Establish the forward slip on final and hold that attitude until stopped.
However, I commonly "cheat" whilst flying the tug, crabbing until short final and then establishing the slip. Less pressure on the rudder foot/knee if doing lots of landing in the Pawnee. |
#13
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Do you crab or forward slip in X wind landings
On Sat, 25 Feb 2017 18:30:11 -0800 (PST), Citrus Soaring
wrote: Side slip is the easiest and most powerful form of crosswind correction. Simply use the rudder to keep the nose of the glider parallel to runway center line and lower the upwind wing enough to counter the wind. To much bank and you drift upwind of centerline. Side slip can be maintained all the way to the end of the roll out just by keeping the upwind wing low. If the cross wind is to strong for this method you shouldn't be flying or you should select a different runway. Crab Requires a transition to a side slip just above the ground and almost guarantees a side loaded landing either from kicking to late or to soon and not getting into the side slip quick enough. Forward slips are not really for crosswind correction they are more for glide path control. I wonder about the different methods that are taught - in Europe the only acceptable method is crab, aligning with rhe runway heading during the flare, and immediately touching down. Priority is to keep the wings level all the time to reduce the chances of a ground loop in case of an outlanding. Is it grass strips vs. paved runways which we don't have in Europe? Just a question (since I fly a glider where side slip would always drag the wingtip on the ground before the main wheel touch down): How do you cope with one wingtip lower than the other in case of an outlanding on a field with higher crops? To me the side slip method is a recipe for disaster in this case... Do you teach both methods? Cheers Andreas |
#14
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Do you crab or forward slip in X wind landings
If you have altitude to burn you can do the the entire pattern using turning slips, and this can be a safer maneuver than the standard coordinated turns. Nevertheless, I prefer to crab when taking off and landing in a crosswind, even though you're performing a dreaded skid at the last moment.
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#15
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Do you crab or forward slip in X wind landings
On Sunday, February 26, 2017 at 6:37:23 AM UTC+3, wrote:
Side slip for all the above reasons, especially for instruction. Translating from crab to slip in the flair or just at touchdown is unnecessarily complex. Establish the forward slip on final and hold that attitude until stopped. I don't know anyone who "transitions from crab to slip in the flair [sic]". You simply straighten up with wings level, and accept whatever minor sideways component the crosswind gives you in the two seconds before you touch down. Either you touch down going very slightly sideways, or you yaw a little past the runway heading to align with the direction the glider is actually going. Or, I guess, you could fly your final with a track slightly upwind of runway heading so that your track gets aligned by the crosswind during the flare. It doesn't really matter on the wide lush grass runways we fly gliders from.. Maybe it's different if you're landing on a strip of concrete only a couple of meters wide. Maintaining a slip all the way to the ground isn't a good idea in the long span low wing gliders we train in, especially if the grass is lush and/or uneven. Wings level!!! Again, it may be different in a 2-33. |
#16
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Do you crab or forward slip in X wind landings
On Sunday, February 26, 2017 at 1:00:51 AM UTC+3, Tango Eight wrote:
On Saturday, February 25, 2017 at 4:29:42 PM UTC-5, Martin Gregorie wrote: On Sat, 25 Feb 2017 13:03:59 -0800, Jonathan St. Cloud wrote: Do you crab or forward slip landing in x-winds and why? When I was taught how to fly an airplane the crab method was used when I transitioned to gliders my instructor emphasized forward slip over crab. Years later I have established my procedures, but I thought this might be a useful discussion for newer pilots. Standard UK training, at least when I learnt and I haven't heard any different from our instructors since, is to crab with wings level on approach and kick the glider straight just before touchdown. Another point is that we are taught to do fully held-off landings regardless of the size and surface of the club field on the grounds that its the only sensible way to land out, so we should be able to do it well. I think the two are related because this keeps the wings level while speed bleeds off and its fairly easy to kick the glider straight as it settles. If you also manage a neat two-pointer you can award yourself brownie points as well as knowing that this will help to keep the glider running straight despite any cross-wind. -- martin@ | Martin Gregorie gregorie. | Essex, UK org | What two seater is being used to teach fully held off landings? I doubt people are doing *fully* held off landings i.e. with the glider actually stalling on. More likely it's "held off until the glider is in the same attitude it will have on the ground .. or a tiny bit more" and then allowed to settle in that attitude. As it slows, lift at that AoA becomes insufficient to support the glider, but there is never aerodynamic stall. Maximum AoA / CL is not reached. Once you touch the ground AoA can not be increased, so lift can't be, so you can't start flying again (absent a massive headwind gust) and the *objectives* of a "fully held off" landing are acheived.. Even nose-draggers like the ASK21 have a tail wheel and are landed main-and-tail or slightly tail first. The only exception I know is the PW5. I've never seen anyone land a PW5 tail first. We had an informal challenge to do it when we first got ours. No one managed it. |
#17
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Do you crab or forward slip in X wind landings
At 04:25 26 February 2017, Andreas Maurer wrote:
On Sat, 25 Feb 2017 18:30:11 -0800 (PST), Citrus Soaring wrote: Side slip is the easiest and most powerful form of crosswind correction. Simply use the rudder to keep the nose of the glider parallel to runway center line and lower the upwind wing enough to counter the wind. To much bank and you drift upwind of centerline. Side slip can be maintained all the way to the end of the roll out just by keeping the upwind wing low. If the cross wind is to strong for this method you shouldn't be flying or you should select a different runway. Crab Requires a transition to a side slip just above the ground and almost guarantees a side loaded landing either from kicking to late or to soon and not getting into the side slip quick enough. Forward slips are not really for crosswind correction they are more for glide path control. I wonder about the different methods that are taught - in Europe the only acceptable method is crab, aligning with rhe runway heading during the flare, and immediately touching down. Priority is to keep the wings level all the time to reduce the chances of a ground loop in case of an outlanding. Is it grass strips vs. paved runways which we don't have in Europe? Just a question (since I fly a glider where side slip would always drag the wingtip on the ground before the main wheel touch down): How do you cope with one wingtip lower than the other in case of an outlanding on a field with higher crops? To me the side slip method is a recipe for disaster in this case... Do you teach both methods? Cheers Andreas I think it depends on what you are flying and the surface you are landing on The modern ships like Ventus 3 and arcus seem to have high wing tips as did the early American stuff so slip makes sense The kestrel,nimbus generation ships had low tip clearance and a crab was the only way. I was once told the are only 2 types of Kestrel owners ,those who have ground looped and those who are going to Nice soft grass is much more forgiving of a little sideways slide than high friction paving |
#18
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Do you crab or forward slip in X wind landings
On Sat, 25 Feb 2017 23:19:45 -0800, Bruce Hoult wrote:
On Sunday, February 26, 2017 at 1:00:51 AM UTC+3, Tango Eight wrote: On Saturday, February 25, 2017 at 4:29:42 PM UTC-5, Martin Gregorie wrote: On Sat, 25 Feb 2017 13:03:59 -0800, Jonathan St. Cloud wrote: Do you crab or forward slip landing in x-winds and why? When I was taught how to fly an airplane the crab method was used when I transitioned to gliders my instructor emphasized forward slip over crab. Years later I have established my procedures, but I thought this might be a useful discussion for newer pilots. Standard UK training, at least when I learnt and I haven't heard any different from our instructors since, is to crab with wings level on approach and kick the glider straight just before touchdown. Another point is that we are taught to do fully held-off landings regardless of the size and surface of the club field on the grounds that its the only sensible way to land out, so we should be able to do it well. I think the two are related because this keeps the wings level while speed bleeds off and its fairly easy to kick the glider straight as it settles. If you also manage a neat two-pointer you can award yourself brownie points as well as knowing that this will help to keep the glider running straight despite any cross-wind. -- martin@ | Martin Gregorie gregorie. | Essex, UK org | What two seater is being used to teach fully held off landings? I doubt people are doing *fully* held off landings i.e. with the glider actually stalling on. More likely it's "held off until the glider is in the same attitude it will have on the ground .. or a tiny bit more" and then allowed to settle in that attitude. As it slows, lift at that AoA becomes insufficient to support the glider, but there is never aerodynamic stall. Maximum AoA / CL is not reached. Once you touch the ground AoA can not be increased, so lift can't be, so you can't start flying again (absent a massive headwind gust) and the *objectives* of a "fully held off" landing are acheived. Even nose-draggers like the ASK21 have a tail wheel and are landed main-and-tail or slightly tail first. The only exception I know is the PW5. I've never seen anyone land a PW5 tail first. We had an informal challenge to do it when we first got ours. No one managed it. Good description. I've never flown a PW6, but I have flown a PW5 and suppose its also near impossible to fully hold off. Of course fully held off landings work a treat for ASK-13s and T-21s: both have a nose skid. In my experience my Std Libelle is the hardest glider to hold off for a nice two-point landing, primarily because the weak airbrakes mean that if you start raising the nose even slightly early it will balloon, but its always a nice end to a flight when both wheels touch the floor together. -- martin@ | Martin Gregorie gregorie. | Essex, UK org | |
#19
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Do you crab or forward slip in X wind landings
On Saturday, February 25, 2017 at 4:04:02 PM UTC-5, Jonathan St. Cloud wrote:
Do you crab or forward slip landing in x-winds and why? . . I teach both (a requirement of the FAA Pilot Test Standard), but recommend and almost always use a slip (in the US, that'd be the oxymoronically labelled "side slip", not a "forward slip") in moderate crosswinds. If the xwind is too strong, I switch to as much of a slip as is comfortable to avoid wingtips dinging the runway, then crab. These procedures are more important on paved runways than grass, because the side loads on the gear with even a slightly botched crabbed landing on pavement can cause significant damage. As to "why", it's because the properly executed "side slip" permits a stabilized approach that continues right down into the flare (easier to teach as well), and reduces the risk of side loads on the landing gear. Finally, when the issue of ground loops, grass vs. pavement, or off-airport landings is raised, then the answer changes to "it depends", and the pilot should be skilled in using whatever procedure fits the circumstances. |
#20
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Do you crab or forward slip in X wind landings
This thread is more interesting that I would have guessed. I thought standard practice was to teach both. That's what we did when I was a student pilot. Crabbing was emphasized as the better technique for managing larger cross winds (and we students figured it out, just fine).
It's obvious to any pilot proficient with both slips and crabbing approaches that the cross wind limits of the crabbing approach are vastly higher than what you can manage with slipping alone. About 50%, I'd reckon. see also: Peter Schiff, The Proficient Pilot. best, Evan Ludeman / T8 |
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